Tree of heaven, Ailanthus altissima, is a deciduous tree native to north-east and central China and Taiwan. It was brought to Europe and North America as an ornamental, but became invasive and is now an invasive species of concern in many countries, including Canada. Once established, tree of heaven is difficult to control, with mechanical and chemical options being limited and expensive. Since 2020, CABI has been working with partners to coordinate options for biological control of tree of heaven in Canada.
Parrot feather, Myriophyllum aquaticum, is a very popular garden and ornamental plant and has a long history of invasion worldwide. It was first recorded in Canada in 1980 from British Columbia and has since been recorded in the Lower Mainland and in the USA. Parrot feather forms dense impenetrable mats which affect stream flow, resulting in reduced native species’ richness at local scales, reduced water quality and habitat quality for fish and wildlife, and impacts on human activities. Due to the negative impacts, management of this species is required and a sustainable option is biological control. A biological control programme against parrot feather is already well-developed in South Africa and this project aims to investigate the potential for use in Canada.
Japanese knotweed is a highly invasive weed that impacts severely on native biodiversity and local infrastructure in its introduced range. Whilst chemicals are currently used to control the weed, this approach is costly and unsustainable. Biological control is an alternative method. The damaging leaf-spot fungus, Mycosphaerella polygoni-cuspidati, which attacks the plant in its native range was found not to be suitable as a classical biocontrol agent. However, the pathogen is considered to hold potential as a mycoherbicide. The aim of this project is to undertake proof-of-concept research into a potential mycoherbicide, in collaboration with the private industry.
A new invasive pest of particular concern to Switzerland’s orchard industry is the Comstock mealybug, Pseudococcus comstocki. Originating from Asia, the Comstock mealybug was first detected in 2016 in fruit crops of the Swiss canton of Valais. Following its detection, the mealybug has caused significant local economic damage to apricot, pear and apple production, especially during 2018 and 2019. Chemical control is one way of helping to fight the pest but it has produced mixed, and often, insufficient results. Biological control is another method and this project, therefore, aims to develop a sustainable and environmentally friendly, biological control method for the Comstock mealybug.